Rihanna's "Rude Boy" still #1 this week

Some of you follow my online radio countdown, American Top 50. Did you know you can see the chart for this week's countdown? It's here.

This week, Rihanna spends a fourth week at #1 with "Rude Boy." Lady Gaga scores yet another top 10 with "Alejandro." Usher moves strongly from #8 to #5 with "OMG," and B.o.B is on the verge of scoring both his first #1 hit and another top 10 hit.

Lower down the chart, Travie McCoy's "Billionaire" shoots up 10 to #17, Jamie Foxx is up 11 spots with "Winner," and the Black Eyed Peas zoom from #47 to #30 with "Rock That Body," yet another hit from their album The E.N.D. (The Energy Never Dies).

There are six debuts this week, led by Mike Posner's "Cooler than Me."

American Top 50 is compiled by putting together two great Billboard charts: the Hot 100 and the Mainstream Top 40.